I have only been to the Wakeboard Camp (three times), and have nothing but great things to say about it. The accomodations are a bit rough (think summer camp), but the atmosphere is stellar. The coaches and staff are top notch, the food is incredible, and as said earlier, there are plenty of nearby watering holes for knocking back a few at the end of the day.
You'll get more than enough water time at TWC, and if you're not in fairly good shape, you'll be wishing you didn't get so much riding. (The last time I was there I was extremely out of shape, and by the third day I could hardly move.)
On the other hand, I've heard nothing but good things about the Boarding School too, so I really don't think you'll go wrong with either place.